/Engine/Source/Runtime/Engine/Classes/Materials/MaterialExpressionStrata.h
class UMaterialExpressionStrataUI : public [UMaterialExpressionStrataBSDF](API\Runtime\Engine\Materials\UMaterialExpressionStrataBSDF)
FExpressionInpu...
Color
The output color of the UI element.
FExpressionInpu...
Opacity
The coverage of the UI element: the more the value is high, the less the back buffer will be visible.